This invention relates to a navigation device for a vehicle and a method of navigating a vehicle for navigating a route.
In the conventional navigation device for a vehicle and a method of navigating a vehicle for navigating a route, a destination and the desired display scale are inputted from an operating part. Then, the optimum route is searched for from map data stored in a memory, or the like. With the current position as a starting point, a map containing therein the route searched for within a range corresponding to the inputted display scale is displayed on a display device. Further, the current position of the traveling vehicle is detected by a global positioning system (GPS) receiver, and the route of the vehicle is navigated by successively changing the range of display with the traveling speed.
Among the conventional navigation device for a vehicle and methods of navigating a vehicle, there is a device as follows. Namely, the traffic information on the route searched for by a vehicle information and communication system (VICS) receiver is detected and, where a traffic snarl, a traffic accident, or the like, has occurred in the searched route, a bypass route is searched for. And a message is displayed to notify the occurrence of the traffic snarl, the traffic accident, or the like, in the traveling route, and the display is then switched to the bypass route. Thereafter, a message is displayed to ask a user of the vehicle whether the bypass route will be taken or not.
However, in this kind of navigation device for a vehicle and a method of navigating a vehicle, the traveling route and the bypass route are displayed by switching from one to the other. Therefore, the user is at a loss whether the bypass route should be taken or not.
As a solution to the above-described drawback, among the conventional navigation device for a vehicle and methods of navigating a vehicle, there is a device which divides the display screen into two so as to simultaneously display the traveling route and the bypass route on a display scale that is set by the user.
However, in this kind of navigation device for a vehicle and the method of navigating a vehicle, the display scale that is set by the user ordinarily covers a relatively narrow range that can be seen with eyes. Therefore, the bypass route displayed on the same display scale as the above-described display scale is too narrow to be easily recognized. As a result, it is required for the user to change the display scale of the bypass route.
In any one of the above-described conventional devices, in order for the user to recognize the bypass route accurately, the user is forced to steadily gazing the display screen, which may momentary loose user""s attention to the driving operation. In particular, in a place like an intersection, or the like, where a special care must be paid to the driving operation, steadily gazing the display screen attends with great danger.
This invention has been made to solve the above and other problems and an object thereof is to provide a navigation device for a vehicle and a method of navigating a vehicle which, in case a bypass route is to be displayed due to the occurrence of a traffic snarl, a traffic accident, or the like, in the route along which the vehicle is traveling at present, the traveling route and a bypass route can be easily and accurately recognized without changing a display scale.
Further, another object of the present invention it to provide a navigation device for a vehicle and a method of navigating a vehicle which, in the case of a user is unfamiliar with the place where the utmost attention must be paid to the driving operation or with the driving operation, does not cause the user uneasiness for processing in connection with the selection of the traveling route and the bypass route.
A navigation device for a vehicle according to the present invention includes operating means for inputting therefrom data on a destination and a display scale in accordance with operation; position detecting means for detecting a current position of a vehicle; route setting means for setting a first route from the current position to the destination based on data on the destination inputted by the operating means and the current position detected by the position detecting means; bypass route searching means for searching for a second route to bypass an obstacle when the obstacle which blocks a smooth traveling of the vehicle is detected in the first route; and display control means which sets the range of display of map information to be displayed on a predetermined display device in accordance with the display scale inputted by the operating means so as to successively update the map information to be displayed within the range of display with the traveling of the vehicle, the display control means also displaying the overall second route simultaneously with the first route by setting a new range of display irrespective of the inputted display scale when the second route searched by the bypass route searching means is displayed.
Through this arrangement, when a bypass route is displayed on the route along which the vehicle is traveling at present due to the occurrence of a traffic snarl, a traffic accident, or the like, the present route and the bypass route can be easily and accurately recognized without changing the display scale.
A method of navigating a vehicle according to the present invention includes the steps of: inputting data on a destination and a display scale in accordance with an operation; detecting a current position of the vehicle; setting a first route from the current position to the destination based on data on the inputted destination and the detected current position; searching for a second route to bypass an obstacle when the obstacle which blocks a smooth traveling of the vehicle is detected in the first route; and setting the range of display of map information to be displayed on a predetermined display device in accordance with the inputted display scale so as to successively update the map information to be displayed within the range of display with the traveling of the vehicle, and setting the overall second route irrespective of the inputted display scale when the searched for second route so as to display the overall first route simultaneously with the second route.
Through this arrangement, when a bypass route is displayed on the route along which the vehicle is traveling at present due to the occurrence of a traffic snarl, a traffic accident, or the like, the present route and the bypass route can be easily and accurately recognized without changing the display scale.